Got a very strange problem: IDEA do not show icons in the Project tab.
A few month ago i had the exact same problem, tried to "Invalidate cashes and restart" - no effect, so then i just reinstall my intellij IDEA and this problem get away, So, then i hoped, that I would never came across with this problem again.
But this it came again.
I really do not want to reinstall my IDEA once more, so, maybe u will help me?
P.S. Lives in Belarus, so, sorry for my English C:
Sorry, "ефи" = tab, i forget to switch layout .__.
Seeing a file as the java icon rather than the class icon is a sign that IntelliJ IDEA is not "seeing" the .java file on the source path. The most common cause is a misconfiguration. For example a source/src directory not being marked as source in the IntelliJ IDEA Project Structure. Looking at your sceenshot, It looks like your java directory is correctly marked as a source.
Another possible cause is a .java that does not have a class, interface, or enum declaration in it. For example an empy .java file or a standard package-info.java file.
Check the above to make sure those are not the issue. You can also try doing a maven re-impot (open the Maven tool window and click the re-import button . Try it two or three times (waiting for it to finish each time by watching the progress in the lower status bar.) Once or twice over the years I've seen a case where I needed to run the re-import a few times in a row to get an issue to clear up.
Finally, a last cause is corrupting in the index files. You indicated you invalidated the caches and restarted. You can always give that another shot.
If none of the above work, I would just recreate the project. You shouldn't need to reinstall IDEA.
What is your IDEA version?
Please check, is main menu / File / Power Save Mode = On? Can you set it Off?